[cost] Add FB-specific cost model

Reviewed By: ezgicicek

Differential Revision: D17788476

fbshipit-source-id: 7fd34eb8d

infer/src/checkers/costModels.ml

@@ -9,22 +9,6 @@ open! IStd
 module BasicCost = CostDomain.BasicCost
 open BufferOverrunUtils.ModelEnv
 
-module type S = sig
-  val length : Exp.t -> BufferOverrunDomain.Mem.t -> BufferOverrunDomain.Val.t
-end
-
-module Array : S = struct
-  let length arr_exp inferbo_mem =
-    BufferOverrunSemantics.eval_array_locs_length
-      (BufferOverrunSemantics.eval_locs arr_exp inferbo_mem)
-      inferbo_mem
-end
-
-module Collection : S = struct
-  let length coll_exp inferbo_mem =
-    BufferOverrunModels.Collection.eval_collection_length coll_exp inferbo_mem
-end
-
 let linear exp ~of_function {integer_type_widths; location} ~ret:_ inferbo_mem =
   let itv =
     BufferOverrunSemantics.eval integer_type_widths exp inferbo_mem
@@ -40,7 +24,7 @@ let modeled ~of_function {pname; location} ~ret:(_, ret_typ) _ : BasicCost.t =
   CostUtils.of_itv ~itv ~degree_kind:Polynomials.DegreeKind.Linear ~of_function location
 
 
-module BoundsOf (Container : S) = struct
+module BoundsOf (Container : CostUtils.S) = struct
   let of_length exp {location} ~ret:_ mem ~of_function ~degree_kind =
     let itv = Container.length exp mem |> BufferOverrunDomain.Val.get_itv in
     CostUtils.of_itv ~itv ~degree_kind ~of_function location
@@ -118,8 +102,8 @@ module JavaString = struct
     BasicCost.mult n m
 end
 
-module BoundsOfCollection = BoundsOf (Collection)
-module BoundsOfArray = BoundsOf (Array)
+module BoundsOfCollection = BoundsOf (CostUtils.Collection)
+module BoundsOfArray = BoundsOf (CostUtils.Array)
 
 module Call = struct
   let dispatch : (Tenv.t, CostUtils.model) ProcnameDispatcher.Call.dispatcher =

infer/src/checkers/costUtils.ml

@@ -32,3 +32,20 @@ let string_len_range_itv model_env exp ~from mem =
       in
       Itv.minus itv start_itv )
   |> Itv.set_lb_zero
+
+
+module type S = sig
+  val length : Exp.t -> BufferOverrunDomain.Mem.t -> BufferOverrunDomain.Val.t
+end
+
+module Array : S = struct
+  let length arr_exp inferbo_mem =
+    BufferOverrunSemantics.eval_array_locs_length
+      (BufferOverrunSemantics.eval_locs arr_exp inferbo_mem)
+      inferbo_mem
+end
+
+module Collection : S = struct
+  let length coll_exp inferbo_mem =
+    BufferOverrunModels.Collection.eval_collection_length coll_exp inferbo_mem
+end